Variable camber airfoil



2 sheets-sheet 1 Qwuentz July 26, 1932. H. J. HOGAN VARIABLE CAMBER AIRFOIL original Filed ooi. 5, 1928 July 25. 1932 H. J. HOGAN VARIABLE GAMBER AIRFOIL 2 Sheets-Sheet 2 Original Filed Oct. 5, 1928 Patented July 26, 1932 UNITED STATES PATENT OFFICE HERBERT J. HOGAN, F LOS .ANCJIIJIIES CALIFORNIA VLARIABLE CAMBER AIRFOIL Belebf abandoned application Serial No. 310,575, led October 5, `1928. This application led. November 28,

' 1931. Serial No. 577,799i.

This invention relates to an airfoil or wing construction adapted for use in combination with airplanes and embodies an organization by means of which the camber of the airfoil may be adjusted by the pilot to suitthe conditions under which the plane is operatin It is well known to those familiar with the art that the lift and drag upo-n an airplane wing during its flight, are factors which are governed largely by the camber or convexity of the wing. In other words, an airfoil having a camber designedto give a maximum or high lift is not adapted-for use on a plane which will satisfy a demand for high velocity while in the air.

It is possible by means of a high camber lin the airfoil to get away from the ground quickly and to land at a relatively low velocity, but as was previously stated, a pl-ane of this character is-not adapted to be flown at 4a high speed. Numerous attemptshave been made to develop a wing constructionl for airplanes by means of which the ratio between the lift and drag upon the wing may be varied to permit the plane to land and to get away at low speed and at the same time to provide a constructionin which the plane may be flown at a high speed. There are three principal methods of 'attacking this problem," one of which isi/to provide` a wing having a variable area, the second is to provide a wing withforward slots or openings which may be adjusted toproduce the desired characteristic, and the third method, which applicant has employed and which should theoretically be the most successful, is to vary the camber of the wing.

In the last mentioned methodA means must be provided for adjusting the camber or convexity of the wing at any time to produce the desired lifting .characteristics and, in such an organization, it should be possible to set the camber while the plane is on the ground to produce a maximum lifting power in the wings at low speed. making it possible for the plane to leave the ground in a relative short distance without necessitating the high velocity generally employed. When the plane is in the air, the camber can be set to accommodate the plane for maximum speed conditions or varied to meet'ordinary cruising conditions, and while the plane is being brought to the ground or landed, the camber can again be adjusted for producing maximum lift, this adjustment making it possible to bring the plane to the ground at a low speed.

It is therefore an object of this invention to produce an organization of the class described in which the camber of the wing may be adjusted by the pilot to suit the particular conditions under which the plane is operating. i

It is a further object of the invention to develop a device of the character described which is sturdy and light in construction and is positive in its operation.

The general construction of this invention embodies an airfoil comprising a main longitudinal center section which may be defined as being substantially rigid or positionally fixedrelative to the fuselage. Pivotally attached to the forward and rear edges of this center vsection are an adjustable front section and an adjustable rear section respectively.

These mentioned adjustable sections embody a plurality 'of panels which are pivotally connected to each other to form units, the

units in turnbeing pivotally connected to 'the j xed section.

Means are provided for moving the panel units rotatablyy about the edges of the'main center section, such movement being effective to vary the convexity or camber of the entire wing section;

In the preferred form of the invention, this last mentioned movement is imparted to the units through a systemv of worm and beveled gears which are controlled from a main drive shaft which in turn is adapted to be operated from a point in the pilots cockpit.

Details in the construction of the invention, together with other objects attending its production, will be better understood from the following description of an. illustrated embodiment thereof as shown in the accompanying drawings in which,

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resented by the line 3 3 in Fig. 1.

foil may be adjusted by means of this inven.

Fig. 4 is an enlarged partial sectional elevation taken substantially in a plane represented by the line 4 4 in Fig. 1.

Fig. 5' is an enlarged sectional plan view taken substantially in a plane represented by the line 5--5 in Fig. 3.

Fig. Gis an enlarged sectional plan view taken substantially 1n a plane represented by line 6-6in Fig. 4.

Fig. 7 is a diagrammatic view illustrating the manner in which the camber of the airtion.

. More particularly describing the invention as Iillustrated in the drawings, referencev nu-l meral'll indicatesthe fuselage of an airplane which' is provided with wings or airfolls 12 j land 12, each of the win s embodying a main center section 13 which 1s substantially rigid ndamay be described asbeing posltionally Mounted upon the forwardor leading edge i of 'each wing, is an adjustable front section 14 which com rises a plurality of panels indicated by re erence numerals 15a, 156 and 150, such panels being l pivotally connected with each other, as will be hereinafter dei scribed, to form a single unit, and the rear panel 15a of this unit, which is adjacent the center section 13, is ivotally connected to .the forwardedge of t e section as will also be hereinafter described.

The wings .12 and 12 also .embody adjustable rear sections indicated by reference numeral 16, each of which comprises panels 17a,

176 and 17 c', these panelsv being interconnected with each other and pivoted to the main center section 13 ina manner similar to thatused in the panels 15a, -156 and 15o. It will be noted that the outer surfaces of the panels arev tapered away from .the edges of the center section to provide an entire wing section of uniform curvature.

The center section 13 embodies spar mem-l bers 19 land 20 which may be of any preferred form commonly used in airplaneconstruction and, for the purpose of maintaining shape and rigidity in this section, a plurality of fixed rib members are mounted therein, ysuch members being indicated by reference'numeral 21. v

Each of the panelmembers 15a, 156 and 15a,- and 17a, 176 and 17o, respectively, is provided with what may be termed segmental rib members, such members being indicated by reference numerals 22a, 226 and 22o, and 23a, 236 and 230, respectively.

Forward control orv pivot plates 24a are pivotally mounted upon the fixed center rib members 21 by means vof pivot-shafts 25a. These control plates 24a are attached to the segmental rib members 22a in any suitable manner such as by means of welding.

It will be understood that the pivotal movement of the control plates 24a, about the pivot shafts 25a, will impart movement to the rib segments 22a and, as illustrated in Fig. 3, a secondset of pivot shafts 256 eX- tend through the rib segments 22a, each of these shafts having rigidly mounted thereon control plates 246. The forward end of the control plates 246 are in turn attached to therib segments. 226 and the pivotal movement imparted theretoby means of the shafts 256 is effective to impart rotation to the ate shafts indicated by reference numeral 27.

These shafts are supported by suitable crossbearing members 28 and 28,the bearing members being mounted in any suitable man- .ner between adjacent parallel pivot plates.

The shafts 27 are upwardly provided with wormv wheels 29, 'each of which is in turn adapted to receive rotation from a worm 30 mounted upon suitable control shafts indicated by reference numeral 31. The lower ends of the shafts 27 are provided with worms 32 which in'turn engage worm wheel seg- V ments 33, the worm wheel segments being gounted upon the pivot shafts 25a, 256 and It will be understood from this construction that a synchronous rotation of all of the control shafts 31 is effectiveto impart a simultaneous movement to all three of the panels 15a, 156 and 15e, the motion of the parts being indicated by the arrows in Figs. 2, 3 and 4.

The construction of the rear adjustable section 16 is similar to that of the front adjustable section 14, each of the panels 17a, 176 and 17o being provided with segmental beams or ribs 23a, 236 and 230. The segmental beams are in turn pivotally connected with each other by `means of the pivot or control plate sections 35a, 356 and 35e, the forward segmental beam 23a being pivotally laus 4.. A wing construction for an airplane embodying: a center section comprising longitudinal spars-andtransverse ribs` said transverse ribsbeing arranged to supportpivot shafts adjacent `opposite edges of said section; pivot shafts rotatably mounted in said ribs; pivot plates rigidly mounted on said pivot shafts;v segmental ribs securedto said pivot plates and adapted to receivesegmental rotation Vabout the edges of said center section, said segmental ribs beingembodied in panel units tapering outwardly from said center section to form a uniformly surfaced airfoil, control shafts rotatably supported by said pivot plates and gear means connecting said control shafts With said pivot shafts for imparting movement .from said `control shafts to said segmental ribs.

5. A Wing constructionfor. an airplane embodying: a center section comprising longiu tudinal spars and transverse ribs, said transverse ribs being arranged to support pivot shafts adjacent opposite edges of said section; pivot shafts rotatably vmounted in said ribs; pivot plates rigidly mounted on said pivotshafts; segmental ribs secured to said pivot plates and adapted to receive segmental rotation about the edges of said center section, said segmental ribs being embodied in panel umts tapering outwardly from said center section to form ya uniformly surfaced airfoil, control shafts rotatably supported by said pivot platesfand gear means connecting said control shafts with said pivot shafts for shaft, an interconnecting shaft supported by oppositely disposed pivot plates, a. Worm Wheel on one.r end of said interconnecting shaft, engagingvsaid Control shaft Worm, a WormonA the opposite end of said interconnecting shaft, and a gear member mounted on said pivot shaft in engagement Withsaid last mentioned worm.

6. A Wing construction for an airplane embodying: avcenter section comprising longitudinal spars and :transverse ribs, said transverse ribs ,being arranged tofsupport pivot shafts `adjacent opposite edgesiof saidfsection; pivot shafts rotatablymounted in said ribs; pivot plates rigidly mounted on said pivotshafts, segmental ribsse-cured to said pivot plates and adapted to receive segmental rotation about the edges of said center section, said segmental ribs being embodied in ypanel unitstapering outwardly from said icenter section to form a uniformly surfaced airfoil, control shafts rotatably supported by said pivot plates and gear means connecting said control shafts with said pivot shafts for im artinor movement from ,said control `shafts to saidrsegmental ribs,` and a main drive shaft adapted to synchronously rotate .said control shafts.4 L y 1 t 1 7 g Avwing Iconstruction fori anairplane embodying: ,a center* section comprising longitudinal spars and transverse ribs, said transverse ribscbeing arranged to support pivot shafts adjacenty opposite edges of said section pivot shafts rotatably mountedlin saidribs; pivot plates yrigidly mounted on said pivot shafts, segmental ribs secured to said pivot plates and adapted to receive segmental rotation about the edges of; said i 8. `A Wing construction for an airplane embodying: a ycenter section comprising longitudinal .spars and transverse ribs, said transverse ribs being arranged to support pivot shafts adjacent opposite edges of` said section; pivot shafts rotatably mounted in said ribsgvpivot plates rigidly mounted on said pivot shafts, segmental lribssecured to said. pivot plates `and adapted to receive segmental rotation about the edges of said center section, said-segmental ribs being embodied in panel unit-s'tapering outwardly from said cent-er section to :form a uniformly surfaced air foil, control shafts rotatably supported bysaid pivot Vplates and gear means connecting said control shafts With said pivot shafts for imparting J movement from said controlshafts to said segmental ribs, each of said Vgear means comprisinga Worm on the control shaft, an interconnecting shaft supported by oppositelydisposed pivot plates, a

Worm'vvheel on one end of said interconnecting shaft, engaging `said control shaft Worm, a Worm on the opposite end of said interconnecting shaft, and a gear `member mounted on said pivot shaft in engagement with said last Amentioned Worm, and a'main driveshaft adaptedto synchronously rotate said controly shafts. f f y 4 ,c `9,. A Wing construction for an airplane embodying: a center section comprising longitudinal spars and transverse ribs, said transverse Vribs vbemg arranged ,to support pivot vshafts adjacent oppositeedges of said sec- `panel units tapering outwardly from said .center section toform a uniformly surfaced airfoil, control shaftsrotatably supported by mounted on control shafts 40, and the lower ends of these interconnecting shafts are provided with Worms 41 adapted to engage segmental gears 42 mounted upon pivot shafts 43.

The Worms 39 mounted upon the control shafts/ are adapted to besynchronously 10- tated to effect the movement of all three panels in a' manner similar to that described above.

Y The4 manner of governing the operation of the forward and rear sets of control shafts 31 and 40, respectively, is best illustrated in Fig. 2 in Which each of the shafts is `illustrated as being provided With Worm Wheels 44. These Worm Wheels are inturn engaged by suitable Wormsy indicated at 45 and46, respectively, Which are mountedupon suitable shaft sections 47 r.and 48, each set of these sections being interconnected by means of universal joints indicated at 49 and 50, and all of the shafts are adapted to receive rotation from beveled gears 51 and' 52. `The beveled gears 51 and 52 are driven by means of a main drive gear53 which is mounted upon a main drive orrcontrolshaft 54. "The shaft 54 extends substantially throughout the entire length of both Wing sections, as is best illustrated in Fig. 1, and is provided with suitable driving means indicated by reference numeral 55, such driving means comprising a geared Wheel 56 which is adapted to be driven in'any suitable manner such as by means ofa chain and crank, indicated at 57. It Will be understood that the Worm gear Vcontrol provides a lock which prevents the panels, comprisingk the front and rear adjustable sections, frornbeing moved from their adjusted position While'the airplane is under the action of the Wind forces during flight. i

Fig. 7 indicates the manner'in which a Wing Vembodying this invention may be adjusted for varying the camber of the airfoil to meet any desirable flying conditions. The

position of the front and rear sections, shown in the full line view, indicate a camber which is perhaps best suited for ordinary flight.

`The dotted line position A shows a high camyber suitable for leaving the ground or landing atloW speed, and the dotted lineposition B illustrates an extreme low camber which might be obtained for high speed conditions.

`The interfitting parts of the panels and the center sectiony are rounded. or curved, as indicated at 59, to provide suitable stream line conditions which `Will reduce the factor of Wind resistance, andJ it Will be understood that the cross-sectional shape of the total Wingsection, the number of panels employed, and the degree to which the camber may be adjusted are dependent largely upon design characteristics of the particular ma chine upon Which the invention is used.

This invention contributes materially to the satisfaction of along felt need in the vairplane industry, it is sturdy and simple in construction andinay be easily adjusted,

each adjustment of the panels being automatically locked against movementas a r`esult of air forces by means of the Worm gearing as has `been previously pointedout.

It Will be understood that, While I have herein described and illustrated one comcomprising a plurality of panels, said panels n including transverse segmental ribs pivotally interconnectedto form units, said units heilig pivotally attached to said main center ribs; and means for imparting kunitary ad- 1 justmentrto said panels for varying the conveXity of said front and rear sections relative to said center section, lsaid segmental ribs being interconnected by means of plates rigidly mounted thereon and pivotally con-Y nected with adjacent segmental ribs. f 2. An airplane Wing construction embody ing: a fixed center section comprisinglongi- -tudmal sparsl and transverse main center ribs; front and rear adjustable sections, each comprising a plurality of panels, said panels including transverse segmental ribs pivotally interconnected by pivotplates to form units, said units being pivotally attached to said main center ribs; and means for imparting unitary adjustment to said panels for varying the convexity of said fro-nt and rear, sections relative to said center section, saidadjust-ing means comprising interconnected gear units mounted upon said' pivot plates in each vpanel and a control shaft operably connected with all of said gear units.

3. A Wing construction for an airplane embodying: a center section comprising longitudinal spars and transverse ribs, said transverse ribs-being arranged to support pivot shafts adjacent opposite edges of said section; pivot shafts rotatably mounted in said ribs;

pivot plates rigidly mounted on said pivot shafts; segmental ribs secured to said pivot 4plates and adapted to receive segmental rotation about the edges of saidcenter section, said segmental ribs being embodied in panel units tapering outwardly from said center section to form a uniformly surfacedairfoil.

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said pivot plates and gear means connecting said control shafts with said pivot shafts for imparting movement from said control shafts tosaid segmentalribs, each of said gear means comprising a Worm on the control shaft, an interconnecting` shaft supported by adapted to synchronously rotate said conv trol shafts, and means, in the cockpit of said airplane for operating saidy main drive shaft.

In testimony whereof, I have hereunto set my handl at Los Angeles, California, this 24th day of November, 1931.

HERBERT J. HOGAN. 

